Hello! Here is an equation that i sometimes use in calculating enthalpy of reaction aA+bB=cC+dD. a,b,c and d are stoechiometric coefficients, A,B,C and D are chemical compounds in reaction. They say that is an other form of the third law of thermodynamic, can one guide me please to derive it? [tex]\Delta[/tex]H=T[[tex]\Delta[/tex][tex]\Phi[/tex]-Rln(K)]. where T is temperature, [tex]\Delta[/tex][tex]\Phi[/tex] is the Gibbs Free energy, R is the ideal gas constant and K is the partial pressure equilibrium constant.